Abstract: A dual-polarized antenna includes a planar line or surface array of reradiating elements of two different polarizations. Each reradiating element in one embodiment is a short-circuited vertical or horizontal dipole. The vertical and horizontal dipoles may be collocated on the array to form crossed short-circuited dipoles. The elements of each polarization form an array separate from the elements of the other polarization. Within each of the two separate arrays, the 1/.lambda. of each reradiator is adjusted to provide a phase shift which causes a collimated beam incident on the array to result in reradiation or "reflection" of energy in the form of a beam converging at a focal point. Therefore, each planar reradiator array acts as a parabolic reflector with a particular focal point. The focal points for the vertical and horizontal arrays are different, and a feed of the appropriate polarization is located at each of the two focal points.

Abstract: A satellite communications system includes a feed array and reflector receiving antenna coupled to a dual-mode network, for generating two channels, with independent signals representing two beams, one for each channel. Each output channel of the dual-mode network contains redundant information relating to a plurality of information channels. In the absence of an interfering signal or intrusion, the combined signals are amplified and block frequency-converted, then de-multiplexed into separate channels, which are each applied through selection switches to a transmitter multiplexer for retransmission. An alternate signal is tapped from each of the two received signal channels, phase controlled, and combined, to produce a combined signal representing a receive antenna beam with a null controllable in position in response to phase. The combined signal is demultiplexed into separate information channels.

Abstract: According to the invention, a two-dimensional active antenna array, operating at a number of different frequencies, is used to achieve directivity in two orthogonal planes, thereby providing a more constrained beam "footprint". The array includes a larger number of amplifiers than a line array, thereby increasing the total power which can be combined in space, to further increase the power in the footprint. For transmission, each of the information channels at a different frequency is applied, as in the prior art, to a different power divider array, each of which may be on a separate board. Power-divided signal from each of the information signal channels is applied to an N-input, M-output power combiner arrangement or board, which combines the signals. Each N.times.M power combiner arrangement includes N.times.M nodes. Each node represents the junction or crossing of one input and one output signal transmission path.

Abstract: An antenna suited for a communications satellite includes two separately located, mutually orthogonally polarized feed antennas such as vertically and horizontally polarized linear horns. The horns feed an active reflector antenna array. The array includes a plurality of mutually orthogonally polarized antenna elements such as crossed dipoles or square patch antenna with cross feeds for two independent orthogonal polarizations. The feeds of the antenna elements are coupled to amplifier modules. Each module includes a circulator for each polarization, coupled to a processor including a low noise amplifier, controlled phase shifter, variable gain amplifier and power amplifier. The output of the power amplifier feeds the antenna element through the circulator. The large number of radiating elements allows high power using power amplifier with relatively modest capabilities.

Abstract: A hollow waveguide includes a conductive peripheral wall arrangement centered on a longitudinal axis. The waveguide is short-circuited at a first transverse plane. A center conductor is connected to the short-circuit and extends along the longitudinal axis to an abrupt open circuit termination at a second transverse plane. The arrangement is fed at a location between the first and second transverse planes to produce both a fundamental waveguide mode and a center-conductor coupled mode. The fundamental mode has an amplitude taper in the horizontal direction but not in the vertical direction. At the abrupt termination, a higher-order waveguide mode is generated which, when phase-shifted by 180.degree., provides an amplitude taper in a vertical direction. A radiating aperture located near the 180.degree. phase shift point produces a radiation pattern which is similar in both the verticla and horizontal planes.

Abstract: A reduced size waveguide directional coupler assembly includes a first rectangular waveguide which is adapted to receive signal at an input port. A conductive septum parallel with a broad wall of the rectangular waveguide divides the signal into two portions flowing in first and second channels within the first waveguide. The septum may be centered between the broad walls, in which case the two signal portions and channel dimensions are the same, or the septum may be off-center, resulting in dissimilar amplitudes of the two signal portions. The coupler also includes a second waveguide. Branch waveguides or other coupling apertures open from the first channel into the second waveguide. That energy not flowing to the second waveguide from the first channel may be routed to an independent output port, or may be recombined with the energy flowing in the second channel and routed to a combined output port.

Abstract: An antenna selectively fed from a square waveguide in one of two orthogonal linear TE.sub.1,0 modes includes a transition between the square waveguide and a larger square horn. A transition arrangement including a plurality of thin conductive elements or vanes is dimensioned and located at the transition to provide a gradual transition between the smaller waveguide dimension and the larger horn dimension in the E plane, and an abrupt transition in the H plane, regardless of the polarization selected. The abrupt transition in the H plane converts some of the TE.sub.1,0 mode energy to the TE.sub.3,0 mode. The radiating aperture is at a predetermined distance from the transition arrangement so that the desired relative phase between the TE.sub.1,0 and TE.sub.3,0 modes may be established. The E-plane aperture distribution is unaffected by the phasing, but the H-plane aperture distribution can be controlled by selection of the appropriate relative phase in order to provide a more linear distribution than TE.sub.

Abstract: A reduced size and weight beam forming network for a circularly polarized N element array antenna system is achieved by interconnecting quadrature couplers without intermediate phase shifters and adding twisted waveguide phase shifters at the coupler outputs to equalize the phase at the array elements.

Abstract: A family of waveguide branch directional couplers having various coupling values is adapted for using the same housing dimensions for all members of the family. The housing includes a conductive block defining first and second spaced-apart parallel rectangular through waveguides. The block also defines a chamber extending between the through waveguides. One or more further conductive blocks in the form of rectangular parallelepipeds are fastened within the chamber and dimensioned to coact with the chamber dimensions to define at least two rectangular branch waveguides extending between the through waveguides. The dimensions of the further blocks are selected to adjust the branch waveguide dimensions to provide the various coupling values.

Abstract: A reconfigurable shaped beam antenna system includes dual mode power divider with the output ports coupled to an equal number of radiators arranged in a row to provide a linear phase progression. One of the output ports of the power divider is selectively coupled to an additional radiator located at the opposite end of the row via 180.degree. phase shifter to maintain the phase progression.